Image processing method and device for fluorescence reaction region of teeth

1. An image processing method for a fluorescence reaction region of teeth, comprising: emitting blue light from a light source to illuminate the teeth in a mouth, so that the teeth generate fluorescence; capturing a first teeth image of the teeth by an image capturing unit; separating the first teeth image into a first red-value image, a first green-value image, and a first blue-value image by a processing unit; transforming the first red value image into a second red value image by the processing unit using a pixel value transforming function, wherein in the step of transforming the first red-value image into the second red-value image, further decreasing a red pixel value of the first red-value image that is smaller than a predetermined value, and increasing a red pixel value that is greater than the predetermined value, wherein an upper limit of the increased red pixel value of the first red-value image is 2n−1, and a lower limit of the decreased red pixel value of the first red-value image is 0, where n is a positive integer; and combining the second red-value image, the first green-value image, and the first blue-value image into a second teeth image by the processing unit.

2. The method as claimed in claim 1 , further comprising: transmitting the second teeth image to a display device to display the second teeth image.

3. The method as claimed in claim 1 , wherein the step of transforming the first red-value image into the second red-value image further comprises: generating a red pixel value correspondence table with the pixel value transforming function using the red pixel values from 0 to 2n−1; and transforming the first red-value image into the second red-value image according to the red pixel value correspondence table.

4. The method as claimed in claim 1 , wherein: the step of reducing the red pixel value that is smaller than the predetermined value is to subtract a first transformed red pixel value from the red pixel value that is smaller than the predetermined value, wherein the first transformed red pixel value is obtained by substituting the red pixel value that is smaller than the predetermined value into a first elliptic function; and the step of increasing the red pixel value that is greater than the predetermined value is to add a second transformed red pixel value to the red pixel value that is greater than the predetermined value plus, wherein the second transformed red pixel value is obtained by substituting the red pixel value that is greater than the predetermined value into a second elliptic function.

5. An image processing device for a fluorescence reaction region of teeth, comprising: a light source, disposed to emit blue light to illuminate the teeth in a mouth, so that the teeth generate fluorescence; an image capturing unit, disposed to capture a first teeth image of the teeth; a processing unit, disposed to process the first teeth image, wherein the step in which the processing unit processes the first teeth image comprises: separating the first teeth image into a first red-value image, a first green-value image, and a first blue-value image; transforming the first red-value image into a second red-value image by using a pixel value transforming function, wherein in the step of transforming the first red-value image into the second red-value image, further decreasing a red pixel value of the first red-value image that is smaller than a predetermined value, and increasing a red pixel value that is greater than the predetermined value, wherein an upper limit of the increased red pixel value of the first red-value image is 2n−1, and a lower limit of the decreased red pixel value of the first red-value image is 0, where n is a positive integer; and combining the second red-value image, the first green-value image, and the first blue-value image into a second teeth image.

6. The image processing device as claimed in claim 5 , further comprising: a storage device, storing the pixel value transforming function and a red pixel value correspondence table, wherein the processing unit transforms the first red-value image into the second red-value image according to the red pixel value correspondence table.

7. The image processing device as claimed in claim 5 , wherein the pixel value transforming function comprises: a first elliptic function, performed by the processing unit to decrease the red pixel value that is smaller than the predetermined value, wherein the processing unit substitutes the red pixel value that is smaller than the predetermined value into the first elliptic function to obtain a first transformed red pixel value, and then subtracts the first transformed red pixel value from the red pixel value that is smaller than the predetermined value; and a second elliptic function, performed by the processing unit to increase the red pixel value that is greater than the predetermined value, wherein the processing unit substitutes the red pixel value that is greater than the predetermined value into the second elliptic function to obtain a second transformed red pixel value, and then adds the second transformed red pixel value to the red pixel value that is greater than the predetermined value.